THESAURUS
sonar
astronavigation, bathometry, bathymetry, celestial navigation, chronometer, coastwise navigation, consolan, dead reckoning, depth sounding, echo sounding, echolocation, fathomage, fathoming, fix, line of position, loran, oceanography, pilotage, plane sailing, point-to-point navigation, radar, radio beacon, radio navigation, sextant, shoran, sofar, sounding, soundings, tables, water
ROGET THESAURUS
sonar
Depth
N
depth, deepness, profundity, depression, hollow, pit, shaft, well, crater, gulf, bowels of the earth, botttomless pit, hell, soundings, depth of water, water, draught, submersion, plummet, sound, probe, sounding rod, sounding line, lead, bathymetry,
sonar, side-looking
sonar, bathometer, deep, deep seated, profound, sunk, buried, submerged, subaqueous, submarine, subterranean, subterraneous, subterrene, underground, bottomless, soundless, fathomless, unfathomed, unfathomable, abysmal, deep as a well, bathycolpian, benthal, benthopelagic, downreaching, yawning, knee deep, ankle deep, beyond one's depth, out of one's depth, over head and ears, mark twine, mark twain.